Daytime/Nightime Reception

jdmccall

Super Member
Why, why, why does my NAD C 427 get 30+ stations cleanly in stereo at night, but get practically nothing in the daytime...and can anything be done about it? Weird thing is, some days aren't bad and some nights aren't good...for reception. And, I've never noticed such reception variation in any vehicle I've ever owned. I'm just trying to understand. Maybe I need a vertically polarized antenna like the Magnum-Dynalab ST-2 instead of my old horizontal dipole from Radio Shack?
 
Interesting reading even if not the cause:

It's fun when this happens...

Tropospheric ducting- Reality or myth?

A couple weeks ago I got a station on every frequency on my car radio. Which was very confusing because the LCD backlight bulbs are all gone and I have to navigate by tuning through recognized stations.

The only other thing I can think of is that something that only runs in the day is trashing day reception.
 
Might be worth trying another antenna. I recommend something outside bigger than a dipole.
 
I had a day off yesterday so I was playing around with my fm antenna connections. I pulled out an old pair of vhf rabbit ears and attached it to my tuner's input. Surprise, surprise! I got way better reception with this 1950's gizmo than I did when connected to my Radio Shack roof antenna (omnidirectional). What's going on here? Obviously something ain't right! Either I have a bad connection(s) or my 20 year old, $17 RS antenna ain't cuttin' the mustard anymore. Does 75 Ohm coax copper conductor need to be shiny new on the terminated ends to work properly? Mine aren't. The lead in goes like this: antenna --- 300 to 75 Ohm balun --- 15' RG6 --- connection to house --- 30' RG6 --- wall plate connection --- 6' RG6 --- tuner. So there's lot's of potential for bad connections; especially outside! Grrrrrrr! Work to do!
 
It's that special time of year again when tropo stations start rolling in at night totally crapping out the local stations.
Enjoy it while it lasts. You may be able to do some FM DXing which is always fun.
 
jdm, I'm in the same boat, outdoor antenna doesnt pick up worth a darn. Hooked up a old Bic Beam box and it was like magic. Thinking of running good ole 300 ohm wire straight from the antenna to my receiver, forget the balums... Al
 
Wow, I think we're on the same wavelength! After the good results with the old rabbit ears, I ordered a Terk FM+ from B&H. It was only $13 and I read many positive reviews, so we'll see what happens. If it's not satisfactory on my main system, I'm sure I can use it somewhere else. Then I might up the ante and try the Godar 500. It's $50 so we're getting into serious money but it should be about as good an indoor antenna as there is. And if that fails, it's back to square one.
 
Terk tends to suck, but sometimes you get lucky. As far as outdoor antennas go, yall just ain't got the right one ...

fm-antenna-stack.jpg


The FM1 vertical is hard to beat, but expensive. I augment with an Antenna Craft FM6 pointed directly at my favorite low watt college station and get crystal clear reception. They're just ganged at the mast with one feed line coming in to a Magnum Sleuth FM amplifier.

Yes ... I'm serious about my FM!

For you AM afficianados out there, these things are magic!

4317.gif


Not made any more, but easy enough to find. Just set it beside the radio and point it at the station you want for some major signal gain over the built in ferrite bar.
 
SKizo, my outdoor antenna looks similar to yours, one less element.... its mounted up under the roof of my outside deck in a apt building.(second floor). I ran RG59 from the balum on the antenna into my apt, probably 40 feet and then to another 75 ohm to 300 balum which hooks to my Fisher.

A good friend of mine suggested I get rid of the balums altogether and just run 300 ohm straight from the antenna to the receiver. Going to try that next. :) Al
 
Why, why, why does my NAD C 427 get 30+ stations cleanly in stereo at night, but get practically nothing in the daytime...and can anything be done about it? Weird thing is, some days aren't bad and some nights aren't good...for reception. And, I've never noticed such reception variation in any vehicle I've ever owned. I'm just trying to understand. Maybe I need a vertically polarized antenna like the Magnum-Dynalab ST-2 instead of my old horizontal dipole from Radio Shack?

You`re aware that the sun throws off a tremendous amount of radiation, yes ? Solar eruptions are largely responsible for poor reception.... FM waves being extremely short, and easily overpowered by the sun`s abundant energy. Nighttime, we`re turned 180 degrees (or so) away from that energy, so the FM waves suffer less molestation in their travels.

I live in an area of marginal reception (about 30 miles from Philly, and 60 miles from NYC), so I took a stab at making my own antenna. I pulled this design off the `net, and spent an hour or two assembling it. Mounted it in the highest point of my attic....it works very well. I made the mount rotatable for best aim. Now I get Philly, NY, Allentown, Princeton, and many more fringe area stations (especially at night).
 

Attachments

  • FM antenna #1 (640x640).jpg
    FM antenna #1 (640x640).jpg
    172.8 KB · Views: 18
  • FM antenna #2 (640x640).jpg
    FM antenna #2 (640x640).jpg
    182.3 KB · Views: 20
Sun actions...

Have been very active lately. The coronal outburst(I think that's what they call it, bigger than several Earths) last week was tremendous.
I hope that this may have been the reason for your reception problems because it happens irregularly and with little predictibillity.

Try what you did last week(if you did last week) again. It may be different.

Paul
 
I know the sun and other atmospheric conditions can effect radio transmission, but the thing is, I don't hear these effects on car radios or portables near to the extremes that I do on my indoor hi-fi FM tuners. Why should that be?

I have considered the Magnum-Dynalab ST-2, and I even bought another 5' mast section that would get a vertical antenna up above the peak of my roof. But I'm exploring other cheaper options first. The main problem may be my location. We're in a TV dead zone (hard to get much of anything OTA without a tower and a rotator) and so FM suffers for the same reason. We have one local station and the next closest are 20-40 miles away. Then after that it's 50-60 miles. The big city (KC MO) stations are over 100 miles away and conditions have to be just right to get any of those cleanly.

I don't want to do a rotator, but there is a cluster of stations in more or less one direction, so I could use our big Antenna Craft VHF-UHF-FM antenna instead of the little FM Omni and see how that works. I also need to do a roof-down inspection and repair of all connections...I need a day off!
 
I know the sun and other atmospheric conditions can effect radio transmission, but the thing is, I don't hear these effects on car radios or portables near to the extremes that I do on my indoor hi-fi FM tuners. Why should that be?

A car radio or portable might quietly slip out of stereo mode and reduce the hiss on a weak signal. So they might be "hiding" the trouble they're having.

What does FM Fool say about your location?

FM Fool
 
SKizo, my outdoor antenna looks similar to yours, one less element.... its mounted up under the roof of my outside deck in a apt building.(second floor). I ran RG59 from the balum on the antenna into my apt, probably 40 feet and then to another 75 ohm to 300 balum which hooks to my Fisher.

A good friend of mine suggested I get rid of the balums altogether and just run 300 ohm straight from the antenna to the receiver. Going to try that next. :) Al

I think you are meaning to say "BALUN" which means Balanced to Unbalanced or shortened to the abbreviation of "Balun" another device when using Unbalanced to Unbalanced or "UnUn" means just that.

300 Ohm twin lead is "balanced" and Coax or for example 75 Ohm cable is unbalanced. The type of lead is either two equal conductors of the same type or one inner conductor with an braided outer sleve to make up the 2 conductor cable. since the coaxial cable is of different types of conductors they are considered unbalanced.

A Balun (for example)is used to convert a 300 Ohm feed line to 75 Ohm coaxial line hence the difference of connectors such as screw terminals to a chassis mounted "F" connector and the corresponding twist on "F" connector usually referred to as Male/Female style connectors.

It is used to change the resistance of the two leads into a "matched" resistance that allows signal to flow easier and provide a better matched feed line into the receiver from the antenna.
Hope that helps to clear thing up a bit.

Hermit
 
I know the sun and other atmospheric conditions can effect radio transmission, but the thing is, I don't hear these effects on car radios or portables near to the extremes that I do on my indoor hi-fi FM tuners. Why should that be?

I have considered the Magnum-Dynalab ST-2, and I even bought another 5' mast section that would get a vertical antenna up above the peak of my roof. But I'm exploring other cheaper options first. The main problem may be my location. We're in a TV dead zone (hard to get much of anything OTA without a tower and a rotator) and so FM suffers for the same reason. We have one local station and the next closest are 20-40 miles away. Then after that it's 50-60 miles. The big city (KC MO) stations are over 100 miles away and conditions have to be just right to get any of those cleanly.

I don't want to do a rotator, but there is a cluster of stations in more or less one direction, so I could use our big Antenna Craft VHF-UHF-FM antenna instead of the little FM Omni and see how that works. I also need to do a roof-down inspection and repair of all connections...I need a day off!

One thing that happens is while we often use Horizontal beam (yagi) antennas for FM the broadcast station is using a Vertical transmitting tower. the signals will bounce off the Ionosphere and the direction or orientation of the original signals will change and antennas regardless of orientation will pick up the signals. The frequency of the signals are also dependent on distance from it. VHF (FM) signals are more "line of sight" in nature due to frequency 88-108 MHZ than say a AM signal on .5 to 1.7 Mhz, in addition the FM or Frequency Modulation signal is different to the AM or Amplitude Modulated signal.

The AM signal will tend to follow the curvature of the earth better than a VHF FM signal. that said, it is still possible to pick up or receive signals from a distance (DX) due to many factors Tropospheric Ducting, Atmospheric changes, Sun Spots and many more factors causing either ease and/or difficulty in signal reception.

Please search FM and AM radio signals, Broadcasting for some more details.

Hermit
 
A car radio or portable might quietly slip out of stereo mode and reduce the hiss on a weak signal. So they might be "hiding" the trouble they're having.

What does FM Fool say about your location?

FM Fool

FM Fool? Cool! A wealth of information! Never heard of that, so thanks! Very interesting!

One thing that happens is while we often use Horizontal beam (yagi) antennas for FM the broadcast station is using a Vertical transmitting tower. the signals will bounce off the Ionosphere and the direction or orientation of the original signals will change and antennas regardless of orientation will pick up the signals. The frequency of the signals are also dependent on distance from it. VHF (FM) signals are more "line of sight" in nature due to frequency 88-108 MHZ than say a AM signal on .5 to 1.7 Mhz, in addition the FM or Frequency Modulation signal is different to the AM or Amplitude Modulated signal.

The AM signal will tend to follow the curvature of the earth better than a VHF FM signal. that said, it is still possible to pick up or receive signals from a distance (DX) due to many factors Tropospheric Ducting, Atmospheric changes, Sun Spots and many more factors causing either ease and/or difficulty in signal reception.

Please search FM and AM radio signals, Broadcasting for some more details.

Hermit

loopstick and Hermit: THANK YOU! Your knowledge and help is much appreciated! I've been studying FM a bit lately and I've got to say I find it all fascinating.
 
I think you are meaning to say "BALUN" which means Balanced to Unbalanced or shortened to the abbreviation of "Balun" another device when using Unbalanced to Unbalanced or "UnUn" means just that.

300 Ohm twin lead is "balanced" and Coax or for example 75 Ohm cable is unbalanced. The type of lead is either two equal conductors of the same type or one inner conductor with an braided outer sleve to make up the 2 conductor cable. since the coaxial cable is of different types of conductors they are considered unbalanced.

A Balun (for example)is used to convert a 300 Ohm feed line to 75 Ohm coaxial line hence the difference of connectors such as screw terminals to a chassis mounted "F" connector and the corresponding twist on "F" connector usually referred to as Male/Female style connectors.

It is used to change the resistance of the two leads into a "matched" resistance that allows signal to flow easier and provide a better matched feed line into the receiver from the antenna.
Hope that helps to clear thing up a bit.

Hermit

Thanks Hermit, appreciate the help! Soon as I can get some 300 ohm wire I will report back. :) AL
 
It's that special time of year again when tropo stations start rolling in at night totally crapping out the local stations.
Enjoy it while it lasts. You may be able to do some FM DXing which is always fun.

Yeah, about 15 yrs ago, it was a GLORIOUS afternoon, in the spring-Clear, & cool. I hooked up a JVC CX-500US to an FM antenna on my granmother's apt house, & was BLOWN AWAY... The FM band was one solid station.. I was picking up stuff from near Atlanta, to Roanoke, Virginia.. The JVC was an "All-In-Wonder", no great shakes as for as sensitivity was concerned, but it SHONE on that day. I live across the street & on a little "Rise" from their now, I someday wanna get me a Rohn 40-60' tower, & I have a really good FM antenna -a ginormous Winegard- & a rotator, & distribution amp. Then, Watch Out !
 
Indeed. And SandyG needs him a HH Scott or McIntosh tuner to go with that setup too. A MR 78 on super narrow, and his DX options would be mind boggling during summertime tropospheric ducting
 
To paraphrase Tom Snyder, it's great catching the music flying through the air! Day off tomorrow...hoping to tackle outdoor antenna...add 5' mast section and redo all connections.
 
Back
Top Bottom